In a communication device, for example, it is important to ensure a desired bit error rate (BER) independently upon the state of a propagation environment, such as that in the sea or in the air, thereby providing an improvement in the transmission capacity and achieving low power consumption.
The following patent reference 1 discloses a communication device that performs laser communications between two spatially distant points by using multiple beams and according to a user's operation information inputted from an external inputter.
In this communication device, requirements for variations, such as the direction of angular displacement of the beam axis of each of the multiple beams used for the laser communications, and a pointing error for the communications partner, are set, and the divergence and the number of beams of the laser are determined according to the requirements for variations.
Further, a telescope for laser beam transmission is controlled according to the requirements for variations, so that a plurality of lasers are transmitted to the communications partner.
As a result, because laser communications can be implemented by using the multiple beams for which variations in the intensity of light received by the communications partner are optimized, the variations in the intensity of light received by the communications partner can be reduced, and communicative stabilization can be achieved.